Heretofore it was known to make structures of various types of carbon fibers and composite materials.
U.S. Pat. No. 4,182,495, granted to Borgmeier et al. discloses a method of construction using graphite or carbon fiber preimpregnated tape having a low temperature cure epoxy resin system. U.S. Pat. No. 4,373,006 to Galasso et al. discloses composite materials containing silicon carbide coated fibers.
U.S. Pat. No. 3,853,506 and U.S. Pat. No. 3,900,675 to Olcott, and U.S. Pat. No. 3,980,105 to Myskowski disclose structures utilizing pyrolytic graphite. While U.S. Pat. No. 4,397,901 to Warren is directed to a method of making a composite article comprising a carbon fibrous substrate, including a pyrolytic carbon sheath formed about each fiber of the substrate, a metallic carbide, oxide or nitride coating over the coated fibers of the substrate, and an impermeable metallic carbide, oxide or nitride outer protective layer.
Woven composite articles are disclosed in O'Brien et al., U.S. Pat. No. 4,063,684; Fukuta et al., U.S. Pat. No. 4,336,296; and Maistre, U.S. Pat. No. 4,366,658.
One major problem associated with the prior art structures was to provide a highly corrosion or oxidation resistant structure while providing a lightweight, high strength structure.
It is therefore a principal object of the present invention to provide a high strength structure which is lightweight, and yet has a corrosion or oxidation resistant interior, and to a method for forming same.
It is another object of the present invention to provide a structure as aforesaid which is useful in a broad number of heavy duty intensive environment applications.
The aforesaid as well as other objects and advantages will become apparent from a reading of the following description, the adjoined claims and the accompanying drawings, described below.